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A school psychologist tests a new reading app. The treatment group (using the app) improves their reading speed by words per minute from pretest to posttest, while the control group (using standard books) also improves by words per minute. Apply your understanding of pretest-posttest control group designs to state the conclusion the psychologist should draw about the app's effectiveness and why.
Question: A school psychologist tests a new reading app. The treatment group (using the app) improves their reading speed by words per minute from pretest to posttest, while the control group (using standard books) also improves by words per minute. Apply your understanding of pretest-posttest control group designs to state the conclusion the psychologist should draw about the app's effectiveness and why.
Sample answer: The psychologist should conclude that the reading app is not effective. Because the control group showed the same words per minute improvement, the increase in reading speed was likely caused by threats to internal validity (such as maturation or testing) rather than the app itself.
Key points:
- Conclude that the reading app has no actual effect or is not effective.
- Note that both groups showed the same improvement of words per minute.
- Apply the concept that the improvement is due to threats to internal validity (e.g., testing or maturation) rather than the app.
Feedback: Correct. If both the treatment and control groups show identical improvement, the change is attributed to threats like maturation or testing rather than the treatment. Thus, the app has no actual treatment effect.
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Research Methods in Psychology - 4th American Edition @ KPU
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A school psychologist tests a new reading app. The treatment group (using the app) improves their reading speed by words per minute from pretest to posttest, while the control group (using standard books) also improves by words per minute. Apply your understanding of pretest-posttest control group designs to state the conclusion the psychologist should draw about the app's effectiveness and why.